INFO: task kworker/1:3:490 blocked for more than 122 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:3 state:D stack:0 pid:490 tgid:490 ppid:2 flags:0x00004000 Workqueue: events fqdir_free_fn Call Trace: context_switch kernel/sched/core.c:5945 [inline] __schedule+0x1322/0x1df0 kernel/sched/core.c:7791 __schedule_loop kernel/sched/core.c:7872 [inline] schedule+0xc6/0x240 kernel/sched/core.c:7887 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common kernel/sched/completion.c:116 [inline] wait_for_common+0x359/0x630 kernel/sched/completion.c:127 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148 rcu_barrier+0x415/0x530 kernel/rcu/tree.c:4657 fqdir_free_fn+0x36/0x150 net/ipv4/inet_fragment.c:167 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d5/0x1020 kernel/workqueue.c:3319 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400 kthread+0x2c7/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 26040f0ed9382bf65720d717d6d6db2d10869199 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120 dump_stack+0x19/0x20 lib/dump_stack.c:129 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline] watchdog+0xd8f/0xed0 kernel/hung_task.c:423 kthread+0x2c7/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 281 Comm: sshd-session Not tainted syzkaller #0 26040f0ed9382bf65720d717d6d6db2d10869199 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:fib6_check_expired include/net/ip6_fib.h:280 [inline] RIP: 0010:__find_rr_leaf+0x16f/0x790 net/ipv6/route.c:843 Code: 00 e8 85 3d 9e fc eb 05 e8 7e 3d 9e fc 49 8d 5e 64 49 89 df 49 c1 ef 03 43 0f b6 04 2f 84 c0 0f 85 9f 02 00 00 48 89 5c 24 78 <8b> 1b 89 de 81 e6 00 00 40 00 31 ff e8 90 41 9e fc 89 d8 25 00 00 RSP: 0018:ffffc9000022fd00 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888109fd8464 RCX: ffff888107addf00 RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000100 RBP: ffffc9000022fe58 R08: ffffc9000022ff80 R09: ffffc9000022ff90 R10: ffffc900002300f0 R11: fffff52000046022 R12: 0000000000000100 R13: dffffc0000000000 R14: ffff888109fd8400 R15: 1ffff110213fb08c FS: 00007f37c5c7d300(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0168f07d60 CR3: 0000000103eca000 CR4: 00000000003526b0 Call Trace: find_rr_leaf net/ipv6/route.c:890 [inline] rt6_select net/ipv6/route.c:934 [inline] fib6_table_lookup+0x2c5/0x9b0 net/ipv6/route.c:2230 ip6_pol_route+0x167/0x12c0 net/ipv6/route.c:2266 ip6_pol_route_input+0x5a/0x80 net/ipv6/route.c:2323 pol_lookup_func include/net/ip6_fib.h:626 [inline] fib6_rule_lookup+0x4cc/0x6b0 net/ipv6/fib6_rules.c:117 ip6_route_input_lookup net/ipv6/route.c:2335 [inline] ip6_route_input+0x59f/0x8d0 net/ipv6/route.c:2631 ip6_rcv_finish_core net/ipv6/ip6_input.c:66 [inline] ip6_rcv_finish+0x15a/0x3c0 net/ipv6/ip6_input.c:77 NF_HOOK include/linux/netfilter.h:317 [inline] ipv6_rcv+0xed/0x220 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core net/core/dev.c:5757 [inline] __netif_receive_skb net/core/dev.c:5870 [inline] netif_receive_skb_internal net/core/dev.c:5956 [inline] netif_receive_skb+0x147/0x7b0 net/core/dev.c:6015 br_netif_receive_skb net/bridge/br_input.c:30 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] br_pass_frame_up+0x126/0x1c0 net/bridge/br_input.c:70 br_handle_frame_finish+0x12d9/0x1720 net/bridge/br_input.c:221 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline] br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424 __netif_receive_skb_core+0xf4b/0x3940 net/core/dev.c:5651 __netif_receive_skb_one_core net/core/dev.c:5755 [inline] __netif_receive_skb net/core/dev.c:5870 [inline] process_backlog+0x3e5/0xae0 net/core/dev.c:6206 __napi_poll+0xd3/0x610 net/core/dev.c:6857 napi_poll net/core/dev.c:6926 [inline] net_rx_action+0x584/0xce0 net/core/dev.c:7048 handle_softirqs+0x1ab/0x630 kernel/softirq.c:621 __do_softirq+0xf/0x16 kernel/softirq.c:659 do_softirq+0xa6/0x100 kernel/softirq.c:503 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_bh+0x54/0x60 kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:396 [inline] lock_sock_nested+0x1f5/0x290 net/core/sock.c:3648 lock_sock include/net/sock.h:1665 [inline] tcp_sendmsg+0x30/0xe0 net/ipv4/tcp.c:1360 inet_sendmsg+0xb7/0x120 net/ipv4/af_inet.c:858 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x3cb/0x4f0 net/socket.c:1166 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x694/0xe80 fs/read_write.c:684 ksys_write+0x141/0x250 fs/read_write.c:737 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x7f/0x90 fs/read_write.c:746 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f37c54a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffed2176940 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f37c5c7d300 RCX: 00007f37c54a7407 RDX: 0000000000000034 RSI: 000055e4daa51170 RDI: 0000000000000004 RBP: 000055e4daa54ca0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001 R13: 00007ffed2176a90 R14: 0000000000000000 R15: 0000000000000004 net_ratelimit: 82854 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) net_ratelimit: 96974 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)